"duplicate Parameters found"

[sadegh-khan]

i have this error : .env/lib/python3.9/site-packages/drf_yasg/utils.py", line 267, in param_list_to_odict assert len(result) == len(parameters), "duplicate Parameters found" AssertionError: duplicate Parameters found

[JoelLefkowitz]

Could you give us the full stack trace and some minimal code to reproduce the error please?

[hzonuz]

That's because you use both filter class and filter backend in the same view. I have this problem too and I don't know how to fix it!

[sobadgirl]

Traceback (most recent call last):
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/django/core/handlers/base.py", line 181, in _get_respon
se
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/django/views/decorators/csrf.py", line 54, in wrapped_v
iew
    return view_func(*args, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/django/views/generic/base.py", line 70, in view
    return self.dispatch(request, *args, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/rest_framework/views.py", line 480, in raise_uncaught_e
xception
    raise exc
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/views.py", line 94, in get
    schema = generator.get_schema(request, self.public)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/generators.py", line 246, in get_schema
    paths, prefix = self.get_paths(endpoints, components, request, public)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/generators.py", line 404, in get_paths
    operation = self.get_operation(view, path, prefix, method, components, request)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/generators.py", line 446, in get_operation
    operation = view_inspector.get_operation(operation_keys)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/inspectors/view.py", line 36, in get_operatio$
    parameters = self.add_manual_parameters(parameters)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/inspectors/view.py", line 172, in add_manual_$arameters
    return merge_params(parameters, manual_parameters)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/utils.py", line 293, in merge_params
    parameters = param_list_to_odict(parameters)
  File "/root/.cache/pypoetry/virtualenvs/api-N-pLUcDe-py3.9/lib/python3.9/site-packages/drf_yasg/utils.py", line 278, in param_list_to_odict
    assert len(result) == len(parameters), "duplicate Parameters found"
AssertionError: duplicate Parameters found

i try drf-yasg first time in an exist project and got this error. i don't know how to reproduce it.

the parameters is:

[Parameter([('name', 'account_type'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'string')]), Parameter([('name', 'user
name'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'string')]), Parameter([('name', 'username_sha'), ('in', 'query'), (
'description', ''), ('required', False), ('type', 'string')]), Parameter([('name', 'created_at'), ('in', 'query'), ('description', ''), ('requir
ed', False), ('type', 'string')]), Parameter([('name', 'account_type'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'str
ing')]), Parameter([('name', 'username'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'string')]), Parameter([('name', '
username_sha'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'string')]), Parameter([('name', 'created_at'), ('in', 'quer
y'), ('description', ''), ('required', False), ('type', 'string')]), Parameter([('name', 'search'), ('in', 'query'), ('description', 'A search t
erm.'), ('required', False), ('type', 'string')]), Parameter([('name', 'ordering'), ('in', 'query'), ('description', 'Which field to use when or
dering the results.'), ('required', False), ('type', 'string')]), Parameter([('name', 'page'), ('in', 'query'), ('description', 'A page number w
ithin the paginated result set.'), ('required', False), ('type', 'integer')]), Parameter([('name', 'limit'), ('in', 'query'), ('description', 'N
umber of results to return per page.'), ('required', False), ('type', 'integer')])]

the result is:

OrderedDict([(('account_type', 'query'), Parameter([('name', 'account_type'), ('in', 'query'), ('description', ''), ('required', False), ('type'
, 'string')])), (('username', 'query'), Parameter([('name', 'username'), ('in', 'query'), ('description', ''), ('required', False), ('type', 'st
ring')])), (('username_sha', 'query'), Parameter([('name', 'username_sha'), ('in', 'query'), ('description', ''), ('required', False), ('type',
'string')])), (('created_at', 'query'), Parameter([('name', 'created_at'), ('in', 'query'), ('description', ''), ('required', False), ('type', '
string')])), (('search', 'query'), Parameter([('name', 'search'), ('in', 'query'), ('description', 'A search term.'), ('required', False), ('typ
e', 'string')])), (('ordering', 'query'), Parameter([('name', 'ordering'), ('in', 'query'), ('description', 'Which field to use when ordering th
e results.'), ('required', False), ('type', 'string')])), (('page', 'query'), Parameter([('name', 'page'), ('in', 'query'), ('description', 'A p
age number within the paginated result set.'), ('required', False), ('type', 'integer')])), (('limit', 'query'), Parameter([('name', 'limit'), (
'in', 'query'), ('description', 'Number of results to return per page.'), ('required', False), ('type', 'integer')]))])

Then, what this is? and what may cause this error and how to avoid it, thanks.

cc @JoelLefkowitz

[Yelinz]

I had this issue because i accidentally had duplicates in DEFAULT_FILTER_BACKEND of REST_FRAMEWORK. Specifically:

    "DEFAULT_FILTER_BACKENDS": (
        "django_filters.rest_framework.DjangoFilterBackend",
        "rest_framework_json_api.django_filters.DjangoFilterBackend",
    ),

After removing one of them it worked again.